I´m professional live and studio engineer and i bought these one to try out if these could replace my trusty MDR-7506:s that are coming to the end of their lifespan.
 
Im always looking good and flat and detailed overallresponce, that is true to original signal and not hyped at any way. I also need headphones that are sturdy, comfy and dampens outside well.
I also need to play them LOUD in time to time, because i need to hear small details, in noisy places (as festivals, clubs and such)
 
In studio, i refer all of my other headphones to my Grado SP125: that are truly amazing and a way a bit dull headgears. And dull is a good thing, when you have to listen by profession and trust that what you are hearing, is all that there is. Grados are openback headphones, so they don´t compare straight to these Sonys, but thats what im after anyway. Older MDR 7506 are truly nice ones, with bass that is not very hyped at al, but goes really low. And there is not many annoying peaks or dips in frequency responce.
 
So what about these new 7510:s? Build quality seems to be very nice and sturdy, even that they are made of plastic. They are very comfy too. When you put them on, first impression is: Whoa! There is bass and its very punchy and detailed. Soundstage is nice and well controlled too. There are details in there ok, and you can hear everything just nice. Dynamics works well and stuf... But are these a bit dull sounding? Too nice? A bit honky at lo mids/upper bass?
So i grabbed my Grados and older Sonys to compare, and ouch! Everything sounds too bright and where did that bass go? ...Ah, this is just how it supposed to sound Hmm that says alot.
 
So, after hours of analytic listening i find that these are nice headphones if you are after for nice and punchy sound, not truefull monitor quality sound but still quite nice and detailed, these might be for you.
Everything sounds pleasant.
If only there would be less going on in 200-300hz and more on around 5 kilos, and slight shelve boost after 12kHz they were a way nicer headphones. Well. at least they are not harsh.
(And yes, you can Eq, them if you must. This worked for me with precise, neutral digi Eq: - 5,5db at 198Hz 0,64Q. -5,5db 290Hz 0,71Q. +4,5db 4050Hz 0,71Q and +5,5db at 12000Hz with modest shelve.)
 
I think that i´m just buying another pair of 7506:s They are not build as well as these one, they are a bit awkward and there are many not-so-good things on them, but they present way better and truefull sonalbalance to me. You know, if it sounds ****ty, i want to hear that too!
 
I think that i bring these ones to the studio, to the tracking room. I bet these works for the tracking drums and such brilliantly!

Hello
 
Just few words about my self: Im professional sound engineer, who enjoys pure and flat sound. Nothing hyped and no snake oil for me thank you.
 
Just got them couple days ago, and i was very anxious to see, how they work for me. Lots of reviews i have read was very promising, but in this thread there have been so many dissapointed people, so...
Package came from post and i plug those in to my iPhone4s and selected my soundcheck track no.1. and boy was i dissapointed. Weak bass, distorted sound and very peaky and unpleasant upper mids. Try to fiddle them out and in and try to adjust tips, and what not. Another, pro-audio soundsource did not make any difference.  No gicar. So i thought that these must be bad pair, and mailed to seller who runs local small busines and is specialised in in-ears, so he knows he´s product. He was baffled, but promised to check them out and to send me new pair.
Then i listened my other familiar cans again, just to quadruple check, that it´s not me, and went back to BA100.s and suddenly whoa!!! Very clean and smooth soundstage. Good balance, exept slight overtightnes in upper mids. What happened? Take them off and on again and they sound thin again. Fiddling them in ears and boom, sound is back. So these things are VERY precise, how to place them in ears.
Then i tried foamtips, that came along them and now i found that sweetspot much easier.
 
So how is the overall sound?
It´s quite flat overall. Subs are a tiiinybit shy, but definedly there. Bass is very clear, non hyped and precise and Lo mids are pure and nice. Upper mids are  a bit bright and there are resonance peaks at 3300 and its upper harmonics at 6600 Hz, and that bothers me quite a bit. I´m sure that many people wont even notice, and prefer this as clarity, and in a sense it is: you can find details exelently with these headphones, but do you need to find things that aren´t  naturally so visible? And it would be nice, if they could go a hint higher at the freq range.
 
So overall: At pricepoint, they are very nice. Mick works fine as well. But you neet to adjust them very precise to get good sound off them and if you are like, me and use iems just on the go, when you want good sound, when you go jogging, biking or something like that, it´s a bit hustle. 
So i still prefer my lost (sob) Sound Magic E10:s, wich are cheaper, not quite so flat, but exelent sounding and much more easier to use.
 
PS: I found that when you place them so that cord points up and go from front behind you ear, they seems to settle down much easier.
 
PPS. That distorsion that i mentioned when i first heard them, was in the record. Never before i have noticed it. So yes, they are very precise

Because i am wearing helmet when biking and longboarding i cant use my trusted Sennheiser PX100 on those kind of activity i went in ear.
i didnt´t want to spend much, max 100 euros, because i do my serious listening mainly in my home and to be honest, didn´t think that
you can have proper sound from inear monitors, unless you spend big bucks for it.
Well let me tell you: i was wrong.
 
Sound of these little fellows are very pleasant indeed. Lots of bass and it goes low, but by a lot, i dont mean that they are over hyped. It just is there, when needed.
There are little bump on upper mids, so some songs gould get a bit boxy, but its very minor bump, so you can live with it easily. And what is most important to me:
Vocal range is not harsh! So overall sound is much better that i could expect to get for 100€, but best part was, that these costs only 27€ No brainer!
Nowdays they go everywhere, that im going. So im using them alot. And they are still as good as new. So build quality is exelent.
Cord is a bit stiff wich is good thing, but could get dangled easily, so i bought this thing called wishbone and that take care of that broblem.

I´ve owned these little bastards many years now, and loved every minute. They are compact in size, but huge in sound. And i mean hu-ge!
I remember when i bought these for travelling and to-go-field recording and just could not believe my ears. 
When i compared these on Grado SR60, In some areas these are better!!!
Some says that PX100 are a bit dull and doesn´t have high end sparkle, bu i say that these are remarkable flat in over all sound. Tho they are a bit
bass hevyish, but i think that in portable headphones, wich you use mainly outdoors and such noisy enviroments, it´s a good thing.
 
I have used these so much that cushions wore out and i find that new ones from sennheiser costs quite a bit. But no worries, you can buy Koss porta pro-pads and
have perfect fit and four pairs on price of one senn:s